Abstract: We investigate whether the anticipated risks of increasing maternal work hours for mother–adolescent relationships differ across family structures: Do intensive mothering norms exacerbate these risks particularly for mothers in two-parent biological families or does their partners’ greater involvement significantly mitigate these risks? We predict mothers’ accessible time, engaged time, and the quality of their relationship with their adolescent children using the National Study of Adolescent to Adult Health. Although the association between mothers’ labor force participation and mothers’ accessible time is significantly weaker in stepfather families relative to two-parent biological families, family structure does not moderate the associations between mothers’ labor force participation and mother’s engaged time or the quality of her relationship with her adolescent. We conclude that mothers face strong normative pressure to privilege their relationship with their child even in the face of long work hours and weaker family support.